1 // Copyright 2016 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // +build linux darwin freebsd openbsd netbsd
17 const blockSize = 8 << 10
19 // unknownFileMode is a sentinel (and bogus) os.FileMode
20 // value used to represent a syscall.DT_UNKNOWN Dirent.Type.
21 const unknownFileMode os.FileMode = os.ModeNamedPipe | os.ModeSocket | os.ModeDevice
23 func readDir(dirName string, fn func(dirName, entName string, typ os.FileMode) error) error {
24 fd, err := syscall.Open(dirName, 0, 0)
26 return &os.PathError{Op: "open", Path: dirName, Err: err}
28 defer syscall.Close(fd)
30 // The buffer must be at least a block long.
31 buf := make([]byte, blockSize) // stack-allocated; doesn't escape
32 bufp := 0 // starting read position in buf
33 nbuf := 0 // end valid data in buf
38 nbuf, err = syscall.ReadDirent(fd, buf)
40 return os.NewSyscallError("readdirent", err)
46 consumed, name, typ := parseDirEnt(buf[bufp:nbuf])
48 if name == "" || name == "." || name == ".." {
51 // Fallback for filesystems (like old XFS) that don't
52 // support Dirent.Type and have DT_UNKNOWN (0) there
54 if typ == unknownFileMode {
55 fi, err := os.Lstat(dirName + "/" + name)
57 // It got deleted in the meantime.
58 if os.IsNotExist(err) {
63 typ = fi.Mode() & os.ModeType
65 if skipFiles && typ.IsRegular() {
68 if err := fn(dirName, name, typ); err != nil {
69 if err == ErrSkipFiles {
78 func parseDirEnt(buf []byte) (consumed int, name string, typ os.FileMode) {
79 // golang.org/issue/37269
80 dirent := &syscall.Dirent{}
81 copy((*[unsafe.Sizeof(syscall.Dirent{})]byte)(unsafe.Pointer(dirent))[:], buf)
82 if v := unsafe.Offsetof(dirent.Reclen) + unsafe.Sizeof(dirent.Reclen); uintptr(len(buf)) < v {
83 panic(fmt.Sprintf("buf size of %d smaller than dirent header size %d", len(buf), v))
85 if len(buf) < int(dirent.Reclen) {
86 panic(fmt.Sprintf("buf size %d < record length %d", len(buf), dirent.Reclen))
88 consumed = int(dirent.Reclen)
89 if direntInode(dirent) == 0 { // File absent in directory.
101 case syscall.DT_FIFO:
102 typ = os.ModeNamedPipe
103 case syscall.DT_SOCK:
105 case syscall.DT_UNKNOWN:
106 typ = unknownFileMode
108 // Skip weird things.
109 // It's probably a DT_WHT (http://lwn.net/Articles/325369/)
110 // or something. Revisit if/when this package is moved outside
111 // of goimports. goimports only cares about regular files,
112 // symlinks, and directories.
116 nameBuf := (*[unsafe.Sizeof(dirent.Name)]byte)(unsafe.Pointer(&dirent.Name[0]))
117 nameLen := direntNamlen(dirent)
119 // Special cases for common things:
120 if nameLen == 1 && nameBuf[0] == '.' {
122 } else if nameLen == 2 && nameBuf[0] == '.' && nameBuf[1] == '.' {
125 name = string(nameBuf[:nameLen])